Knowledge · Comparison
What is the difference between LOTO and LOTOTO?
The difference is not whether the isolation is verified – verification is always part of hazardous energy control. The difference is whether verification is visible in the name of the procedure and whether the process treats it as a separate step.
Same principle. LOTOTO gives verification its own name.
The short answer
Short answerLOTO = lockout and tagout. LOTOTO = lockout, tagout and verification of the isolation (Tryout). The principle is the same; LOTOTO emphasises verification as a step in its own right.
How do LOTO and LOTOTO differ in practice?
Short answerMainly in how prominently verification of the isolation is named and separated from the other steps.
| LOTO | LOTOTO | |
|---|---|---|
| Stands for | Lockout – tagout | Lockout – tagout – Tryout |
| Steps in the name | locking, tagging | locking, tagging, verifying |
| Verifying the isolation | part of the procedure, not in the name | a separate, named step |
| Emphasis | securing the isolation points | securing them and verifying the result |
| Risk if applied loosely | lockout is treated as the end of preparation | lower, if the process requires verification before work starts |
Both terms are used in practice. What matters is whether the plant’s procedure actually requires and records verification.
Why do companies use the term LOTOTO?
Short answerSo that verifying the isolation does not remain implicit. With Tryout in the name, it is harder to skip or to merge with lockout.
A lock confirms that someone acted at an isolation point. It does not confirm that the action was effective. The equipment may have another energy source, a wrongly labelled isolation point or residual pressure. Only verification at the equipment reveals such situations.
Naming Tryout explicitly therefore helps in training, in work procedures and in inspections. Everyone knows that one more mandatory step follows lockout. How Tryout is done is described on What is LOTOTO.
ReadDigital work instructionsWhat does this mean for designing a digital process?
Short answerApproval, isolation and verification should be separate steps in a digital process. Tryout should not merge with the approval or with the lockout.
How Tryout is recorded and built into the digital workflow is something we design according to the rules of each plant. Technically, it makes sense to link the record to the equipment or isolation point, the person, the time and the result of the verification.
It is equally important that each energy is confirmed separately; the energy isolation page explains why. Our overall approach is described on the digital LOTOTO page.
A digital record of verification is a worker’s confirmation, not a measurement. The verification itself is always carried out at the equipment.
Which term should you use?
Short answerThe one used in your plant’s rules. More important than the name is that the procedure explicitly includes verification of the isolation.
In English-speaking environments, and in OSHA 29 CFR 1910.147 – used here as a technical reference framework – the term lockout/tagout prevails. In corporate standards and on site you will often come across LOTOTO as well. When introducing a new procedure or digitalising an existing one, we recommend naming Tryout explicitly so that it is visible at every step. The basic principles of lockout and tagout are covered on What is LOTO.
Next step
Is Tryout a separate step in your procedure?
We will review your current procedure with you and propose how to separate approval, isolation and verification in a digital process.